The brief return of shorts weather

Last Sunday, I decided that my break from early morning exercise should be over, so I planned to get up early Monday and do a sweatfest ride.  I was hoping to get back into my early morning routine, because it was working really well for me, until I quit getting up so early.  I managed to get up Monday morning and do my trainer ride, but I gave up again after that.  I've been consistently getting up around 5, but 4 is just too early right now.  It's been too hard for me to get to bed by 8.  Also, it seems slightly silly to be getting up super early to exercise at 4:30 AM when the weather is gorgeous and warm-ish in the afternoons.

This week : 

M : 30 min trainer (7.3)

4.8 mile Pub Run

T : bike 19.7

W : sprint bike 13.4 (19.4 mph, 886 ft)

F : bike 25.3 w/Byron

Sa : bike 13.3 (race photographer)

total bike miles : 79.3

When I first started biking, I felt like it did nothing for my lungs.  They ended up getting weaker because biking was not keeping them in shape like running did.  Now my lungs have gotten so weak, biking is hard.  I have been getting faster on the bike, and now my legs are strong enough for me to ride pretty hard, but I keep running out of oxygen and having to slow down.  I'm hoping that since biking is now making my lungs work harder, it will also help me start to strengthen them back up...